My travel agent did not inform me before I left for Shanghai that there is a visa requirement if the stay exceeds 15 days

Hi
I am a Singaporean. My travel agent did not inform me before I left for Shanghai that there is a visa requirement if the stay exceeds 15 days. I arrived Shanghai on 18 March and will leave Shanghai on 2 Apr. The total actual number of days is 15 days exactly. However, if you count the arrival date, it will be 16 days. Can you confirm that there is no need for me to apply for a visa?